1. Field of the Invention
The present invention relates to a suction pad with a temperature control mechanism, for attracting a workpiece under vacuum.
2. Description of the Prior Art
Suction pads, for example, connected to a vacuum source are used to transfer cathode-ray tubes with a fluorescent material coated on the back of the glass screen, workpieces of synthetic resin, or the like. The suction pads are more advantageous than feeders with workpiece gripping mechanisms because the suction pads do not cause damage to the workpieces as they are attracted under vacuum while being transferred by the suction pads.
Generally, the suction pads are used at room temperature for conveying workpieces.
When a workpiece, e.g., a part of a cathode-ray tube with a fluorescent screen, is to be transferred under vacuum by a suction pad, the fluorescent coating on the screen may be peeled off because of the different temperatures of the workpiece and the suction pad. The difference between the temperatures of a suction pad and a workpiece of synthetic resin is liable to cause the suction pad to leave a pad mark, e.g., a circular pad mark, on the workpiece of synthetic resin while the workpiece is being conveyed by the suction pad, resulting in a reduction in the workpiece quality. The different temperatures of a suction pad and a workpiece attracted under vacuum thereby even tend to deform the workpiece.